1. Field of the Invention
The present invention relates to an electrical connector for electrically connecting an electronic package such as a land grid array (LGA) chip with a circuit substrate such as a printed circuit board (PCB), and particularly to a connector having sidewalls that securely position the electronic package therebetween and that facilitate installation of terminals into the connector.
2. Description of the Prior Art
Land grid array (LGA) electrical connectors are widely used in the connector industry for electrically connecting LGA chips to printed circuit boards (PCBs) in personal computers (PCs). As described in xe2x80x9cNonlinear Analysis Helps Design LGA Connectorsxe2x80x9d (Connector Specifier, February 2001, pp. 18-20), the LGA connector mainly comprises an insulative housing and a multiplicity of terminals. The housing comprises a multiplicity of terminal passageways defined therein in a generally rectangular array for interferentially receiving corresponding terminals. Due to the very high density of the terminal array in a typical LGA chip, the LGA chip need to be precisely seated on the LGA connector to ensure reliable signal transmission between the terminals and the LGA chip. Means for accurately attaching the LGA chip to the LGA connector are disclosed in U.S. Pat. Nos. 4,504,105, 4,621,884, 4,692,790, 5,302,853 and 5,344,334.
Referring to FIG. 4, a conventional connector 6 comprises an insulative housing 60 and a multiplicity of terminals 61 received therein. In forming the connector 6, a carrier strip (not shown) comprises a row of the terminals 61, and a row of connecting sections 610 respectively connecting the terminals 61 with a main body of the carrier strip. The housing 60 comprises four raised sidewalls 62, and a flat base 63 disposed between the four raised sidewalls 62. The base 63 and the sidewalls 62 cooperatively define a space therebetween for receiving an LGA chip (not shown) therein. The base 63 defines a multiplicity of terminal passageways 64 for receiving the terminals 61 therein. When the LGA chip is seated on the LGA connector 6, the four sidewalls 62 can securely engage the LGA chip therebetween. However, installation of terminals 61 into those passageways 64 near the sidewalls 62 is problematic. Once the terminals 61 have been inserted into such passageways 64, the connecting sections 610 must be cut from their corresponding terminals 61. Because the carrier strip is located close to the sidewall 62, there is insufficient space to manipulate the carrier strip to allow easy cutting off of the connecting sections 610. Such manipulation is blocked by the sidewall 62, which is liable to sustain damage as a result.
FIG. 5 shows another conventional LGA connector 6xe2x80x2 devised to overcome the above-described problem. The LGA connector 6xe2x80x2 comprises a housing 60xe2x80x2. The housing 60xe2x80x2 comprises a flat base 63xe2x80x2 and four raised sides 62xe2x80x2 surrounding the base 63xe2x80x2. Two opposite of the sides 62xe2x80x2 each have a sloped surface that slants down toward the base 63xe2x80x2. The sloped surfaces provide additional space to manipulate a carrier strip to allow easy cutting off of connecting sections 610xe2x80x2 from their corresponding terminals 61xe2x80x2. However, the sloped surfaces diminish the original advantage of the sides 62xe2x80x2 being raised. That is, a reduced surface area of the sides 62xe2x80x2 is available to retain the LGA chip therebetween. This can adversely affect the reliability of signal transmission between the terminals 61xe2x80x2 and the LGA chip.
Therefore, a new LGA electrical connector which overcomes the above-mentioned problems is desired.
An object of the present invention is to provide an electrical connector for electrically connecting an electronic package such as an LGA chip with a circuit substrate such as a PCB, whereby the electrical connector can facilitate installation of terminals into a housing thereof.
Another object of the present invention is to provide an electrical connector having sidewalls that securely position an electronic package therebetween and that facilitate installation of terminals into the connector.
To achieve the above objects, an electrical connector in accordance with a preferred embodiment of the present invention is for connecting a land grid array (LGA) chip with a printed circuit board (PCB). The connector includes an insulative housing, and a plurality of terminals received in a plurality of passageways defined in the housing. The housing has a flat base and sidewalls extending upwardly from the base, the base and the sidewalls cooperatively defining a space therebetween for retaining the LGA chip therein. Two opposite of the sidewalls each define a multiplicity of evenly spaced recesses therein, thereby forming a multiplicity of evenly spaced projections.
When terminals are installed near the projections, a common carrier strip connecting the terminals is bent down so that connecting sections of the carrier strip are received in corresponding recesses. Junction portions between the terminals and their respective connecting sections are cut, and a main body of the carrier strip having the connecting sections is removed. The recesses enable the carrier strip to be manipulated so that sufficient space is made available for cutting off of the connecting sections without interfering with the sidewall thereat. The projections provide precise fitting positioning of the LGA chip in the space. This ensures that engagement between the terminals and pins of the LGA chip is accurate and reliable.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: